1. Field of the Invention
The invention relates to an equipment capable of adjusting its height, and more particularly to an equipment which utilizes at least one multi-threaded screw to adjust its height more effectively.
2. Description of the Prior Art
When an equipment, such as a projector, is placed on a plane, the user often adjusts the height of the equipment according to different needs. For example, when the user uses a projector to display images, he/she always desires to adjust the projected images to a position appropriate for watching. In general, most of the conventional projectors utilize the adjuster foot disclosed in a Japan patent to adjust the height. Also, some conventional projectors utilize general single-thread screw to adjust the height.
Referring to FIG. 1, FIG. 1 is a side view illustrating the single-thread screw 1 of the prior art. The lead (L) of the single-thread screw 1 is equal to the pitch (P), as shown in FIG. 1. In other words, when the single-thread screw 1 is rotated in one complete circle, the movement along the axis of the screw 1 is equal to one pitch. It is inefficient for the user when the height needs to be adjusted. Furthermore, there are always two single-thread screws mounted onto the two sides of the conventional projector, such that the user can adjust the height of both sides of the projector at the same time. However, since each of the screws has the same direction of rotation, it is inconvenient for the user to adjust the height with both hands at the same time.
Referring to FIGS. 2A and 2B, FIG. 2A is a sectional view illustrating the adjuster foot 10 of the prior art. FIG. 2B is a sectional view illustrating the button 12 being released from the adjuster foot 10 shown in FIG. 2A. As shown in FIG. 2A, the adjuster foot 10 comprises a button 12, an engaging member 14, a screw rod 16, and a fixed base 18. The screw rod 16 has lots of threads thereon, and the engaging member 14 has lots of grooves capable of cooperating with the thread pitch of the screw rod 16. When the adjuster foot 10 is in a closed position, the grooves of the engaging member 14 engage with the threads of the screw rod 16, as shown in FIG. 2A. When the user wants to adjust the height of the projector (not shown), he/she only needs to press the button 12, so as to get the engaging member 14 moving away from the screw rod 16, as shown in FIG. 2B. In other words, the user can adjust the height of the projector by the screw rod 16. However, the conventional adjuster foot has some drawbacks listed below:                1. The structure of the conventional adjuster foot is complicated, and the cost is high.        2.The adjuster foot cannot support projectors with heavier weight, or the thread will be stripped.        3. The engaging member 14 has to cooperate with the screw rod 16 precisely, or the mechanism may lose the original function.        
Therefore, the scope of the invention is to provide an equipment capable of adjusting its height to solve the aforesaid problems.